Process of separating ore particles in gravity separating mediums



Patented Feb. 2, 1943 PROCESS OF SEPABATING ORE PARTICLES IN GRAVITY SEPARATING ItIEDIUMS Shelton 1'. Cameron. Washington, D. 0., asslgnor,

by mesne assignments, to Minerals Beneficiation Incorporated, Joplin, Mo., a corporation of Delaware No Drawing. Application June 27, 1940, I

' Serial N0. 342,799

2 Claims. (Cl. 209-173) This invention relates to processes for separating ore particles by introducing the particles into a liquid gravity separating medium composed of water and a comminuted solid or solids, the specific gravity of the medium depending upon the particular solid or solids employed and the proportions of water and such solids. When the ore particles are introduced into such a liquid medium all of those particles whose specific gravity exceeds that of the specific gravity of the medium will sink therein, whereas those particles whose specific gravity is less than that of the medium will rise therein, the two classes of particles being removed respectively from the lower portion and the upper portion of the medium. In many cases the difference in the specific gravities of the particles which it is desired to have sink and of the particles which are to fioat is very small, and to secure most effective separation of the'particles according to their specific gravities, the required specific gravity and the liquidity of the medium once established should be maintained during the separating operation.

When the ore particles are introduced into the medium, almost invariably they are accompanied by natural slimes of the ore and other foreign substances, and it has been found that these slimes and substances together with the solids of the medium form small lumps of fiocci and .produce a viscous condition of the separating medium. The viscosity of the medium progressively increases during the operation of the process and with constantly decreasing efiiciency of separation of the ore particles therein and ultimately renders the use of the viscous medium commercially impractical. One of the inevitable results of the gradually increasing viscosity of the separating medium is that the rapidity of separation is decreased and much of the valuable ore that it is desired to save is eliminated with the waste. When this condition occurs the viscous separating medium is removed from the separating tank and treated in purification tanks for the purpose of recovering the comminuted solids of the medium, this recovery being essential in order to reduce the cost of the solids and make the process commercially practical.

The object of the present invention is to maintain the liquidity of the separating medium practically constant by preventing the flocculation of the slimes and solids in the medium and thus obviating the tendency of the medium to become viscous during the operation. To this end, according to the present process, a 1100.

inhibiting agent, such for example, as tri-sodium phosphate, alum, copperas or ferric iron is continuously introduced into the separating tank during the separating operation, the introduction of the reagent being in such amount as is found by test to practically prevent flocculation and consequent viscosity and thus maintain practically constant the liquidity of the medium. This amount may vary with the particular reagent employed and with diflferent ores, such amount, however, being readily determined by tests at the beginning of the operation, when samples of the medium are removed from the separating tank and tested from time to time until the amount of the reagent that will maintain liquidity of the medium is determined.

Owing to its cost and commerical availability,

' tri-sodium phosphate is preferred as the reagent to employ. This continuous introduction into the medium should be just such in amount as to prevent any viscosity of the medium. This much is necessary in order to secure the results of the invention, and any amount over that would be simply waste. Since the conditions which tend to produce viscosity of the medium are constant with a given medium and a given ore and the continuous introduction of the ore particles into the medium, it is a part of the present invention to also continuously introduce the reacting agent in the proper proportions to negative the viscous tendency. This continuous introduction may be secured in any suitable way,

by hand, or by automatic mechanism, the latter being preferred, because it can be accurately adjusted as to the amount and rate of introduction and the avoidance of labor in its operation.

It will be readily seen that by maintaining uniform liquidity of the medium it is at all times eliminate the foreign matter fed in with theore particles.

What is claimed is:

1. The process of separating ore particles which consists in continuously feeding the ore particles to a separating tank containing liquid separating medium consisting of Water and comminuted solids, and maintaining the liquidity of the medium constant by continuously adding a flee-inhibiting agent to the medium in the separating tank and at a rate suflicient to practically prevent flocculation of slimes and the solids of the medium. I

2. The process of separating ore particles which consists in continuously feeding the ore particles to a separating tank containing liquid separating medium consisting of water and comminutcd solids, and maintaining the liquidity of the medium constant by continuously adding trisodium phosphate to the medium in the separating tank and at a rate sumcient to. practically prevent flocculation of slimes and the solids of the medium.

SHELTON T. CAMERON. 

